Exergy Analysis of Oxidative Steam Reforming of Methanol for Hydrogen Producton: Modeling Study

2013 ◽  
Vol 11 (1) ◽  
pp. 489-500 ◽  
Author(s):  
Shashi Kumar ◽  
Nisha Katiyar ◽  
Surendra Kumar ◽  
Snigdha Yadav
Keyword(s):  
Steam Reforming ◽  
Exergy Analysis ◽  
Fixed Bed ◽  
Molar Ratio ◽  
Input Energy ◽  
Exergy Destruction ◽  
Catalytic Reactor ◽  
Steam Reforming Of Methanol ◽  
Molar Ratios ◽  
Higher Temperature

Abstract Hydrogen production by oxidative steam reforming of methanol in a fixed bed catalytic reactor was modeled and simulated. The addition of O2 to feed reduced the temperature in the reformer. 99.86% conversion was obtained at 550 K and S/C molar ratio of unity in steam reforming while it is at 540 K in oxidative steam reforming. Although H2 and CO yields were decreased in oxidative steam reforming in comparison to steam reforming, the reductoin H2 yield was note significant whereas reduction in CO was appreciably high. The thermal and exergy efficiencies were favored by reforming temperature and S/C molar ratios. However, variation in S/C molar ratio showed negligibly small effect on efficiencies. The reforming temperature had a notable influence on the efficiencies. The exergy destruction was found to be lower at higher temperature and S/C molar ratio. Thus, oxidative steam reforming of methanol at 540 K and S/C molar ratio of unity utilizes sufficient amount of input energy in the form of useful work and thermodynamic irreversibilities in the reactor are quantitatively small.

Dimethyldisulphide Hydrodesulphurization on NiCoMo / Al2O3 Catalyst

2017 ◽  
Vol 68 (7) ◽  
pp. 1496-1500
Author(s):  
Rami Doukeh ◽  
Mihaela Bombos ◽  
Ancuta Trifoi ◽  
Minodora Pasare ◽  
Ionut Banu ◽  
...  
Keyword(s):  
Good Accuracy ◽  
Fixed Bed ◽  
Continuous System ◽  
Space Velocity ◽  
Molar Ratio ◽  
Catalytic Reactor ◽  
Liquid Hourly Space Velocity ◽  
Hydrodesulfurization Process ◽  
Al2o3 Catalyst ◽  
Simplified Kinetic Model

Hydrodesulphurization of dimethyldisulphide was performed on Ni-Co-Mo /�-Al2O3 catalyst. The catalyst was characterized by determining the adsorption isotherms, the pore size distribution and the acid strength. Experiments were carried out on a laboratory echipament in continuous system using a fixed bed catalytic reactor at 50-100�C, pressure from 10 barr to 50 barr, the liquid hourly space velocity from 1h-1 to 4h-1 and the molar ratio H2 / dimethyldisulphide 60/1. A simplified kinetic model based on the Langmuir�Hinshelwood theory, for the dimethyldisulphide hydrodesulfurization process of dimethyldisulphide has been proposed. The results show the good accuracy of the model.

Reuse of Fried Oil to Obtain Biodiesel: Zeolites Y as a Catalyst

2007 ◽  
Vol 5 (1) ◽  
Author(s):  
A. Brito ◽  
M. E. Borges ◽  
R. Arvelo ◽  
F. Garcia ◽  
M. C. Diaz ◽  
...  
Keyword(s):  
Fixed Bed ◽  
Weight Ratio ◽  
Degree Of Conversion ◽  
Transesterification Reaction ◽  
Molar Ratio ◽  
Catalytic Reactor ◽  
Reaction Products ◽  
Waste Oil ◽  
Catalytic Effects ◽  
Fried Oil

The transesterification reaction is the most utilized process to obtain biodiesel. Fried oil transesterification reactions with methanol have been studied using several zeolites Y and interchanged with CsCl and KOH. The reaction has been carried out both in a slurry reactor and a fixed bed catalytic reactor. The catalytic effects of zeolites have been tested within a temperature range of 60-476°C, 2.5-5% catalyst/waste oil weight ratio, and 6:1 - 100:1 methanol/oil molar ratio. Cosolvents (THF, n-hexane) in the reaction feedstock effect have also been studied as well as catalyst regeneration effects. Viscosity of both the oil and the transesterification reaction products was determined as an initial guide to investigate the degree of conversion to biodiesel as well as FAME content by GC. When interchanged zeolites are used conversions are improved, getting the best yields (98% FAME) for the Y756 zeolite interchanged with KOH. Viscosities of the reaction product obtained reached values next to diesel standard ones.

Hydrogen Production for PEM Fuel Cells via Oxidative Steam Reforming of Methanol Using Cu-Al Catalysts Modified With Ce and Cr

2006 ◽  
Author(s):  
Sanjay Patel ◽  
K. K. Pant
Keyword(s):  
Fuel Cell ◽  
Hydrogen Production ◽  
Surface Area ◽  
Steam Reforming ◽  
Pem Fuel Cell ◽  
Oxide Catalysts ◽  
Molar Ratio ◽  
X Ray ◽  
Steam Reforming Of Methanol ◽  
Al Oxide

The performance of Cu-Ce-Al-oxide and Cu-Cr-Al-oxide catalysts of varying compositions prepared by co-precipitation method was evaluated for the PEM fuel cell grade hydrogen production via oxidative steam reforming of methanol (OSRM). The limitations of partial oxidation and steam reforming of methanol for the hydrogen production for PEM fuel cell could be overcome using OSRM and can be performed auto-thermally with idealized reaction stoichiomatry. Catalysts surface area and pore volume were determined using N2 adsorption-desorption method. The final elemental compositions were determined using atomic absorption spectroscopy. Crystalline phases of catalyst samples were determined by X-ray diffraction (XRD) technique. Temperature programmed reduction (TPR) demonstrated that the incorporation of Ce improved the copper reducibility significantly compared to Cr promoter. The OSRM was carried out in a fixed bed catalytic reactor. Reaction temperature, contact-time (W/F) and oxygen to methanol (O/M) molar ratio varied from 200–300°C, 3–21 kgcat s mol−1 and 0–0.5 respectively. The steam to methanol (S/M) molar ratio = 1.4 and pressure = 1 atm were kept constant. Catalyst Cu-Ce-Al:30-10-60 exhibited 100% methanol conversion and 152 mmol s−1 kgcat−1 hydrogen production rate at 300°C with carbon monoxide formation as low as 1300 ppm, which reduces the load on preferential oxidation of CO to CO2 (PROX) significantly before feeding the hydrogen rich stream to the PEM fuel cell as a feed. The higher catalytic performance of Ce containing catalysts was attributed to the improved Cu reducibility, higher surface area, and better copper dispersion. Reaction parameters were optimized in order to maximize the hydrogen production and to keep the CO formation as low as possible. The time-on-stream stability test showed that the Cu-Ce-Al-oxide catalysts subjected to a moderate deactivation compared to Cu-Cr-Al-oxide catalysts. The amount of carbon deposited onto the catalysts was determined using TG/DTA thermogravimetric analyzer. C1s spectra were obtained by surface analysis of post reaction catalysts using X-ray photoelectron spectroscopy (XPS) to investigate the nature of coke deposited.

scholarly journals Cu-Ni Nanocatalysts in Mesoporous MCM-41 and TiO2 to Produce Hydrogen for Fuel Cells via Steam Reforming Reactions

2015 ◽  
Vol 1096 ◽  
pp. 161-168 ◽  
Author(s):  
Richard Yeboah Abrokwah ◽  
Vishwanath G. Deshmane ◽  
Sri Lanka Owen ◽  
Debasish Kuila
Keyword(s):  
Surface Area ◽  
Steam Reforming ◽  
Anatase Phase ◽  
High Surface ◽  
Fixed Bed ◽  
Fixed Bed Reactor ◽  
Reaction Products ◽  
One Pot ◽  
Steam Reforming Of Methanol ◽  
Mcm 41

We have synthesized mesoporous SiO2(MCM-41) and TiO2encapsulated bimetallic Cu-Ni nanocatalysts using an optimized one-pot hydrothermal procedure. The catalysts were characterized using BET, XRD, TGA-DSC and HRTEM techniques. While bimetallic Cu-Ni/MCM-41catalysts have high surface area- 634-1000 m2/g, Cu-Ni/TiO2yields surface area of 250-350 m2/g depending on the metal loading (5-10 wt%). The XRD studies confirmed a long range ordered structure in Cu-Ni/MCM-41 and the presence of the catalytically active anatase phase in the crystalline Cu-Ni/TiO2. The results from HRTEM studies were consistent with the mesoporosity of both supports. These catalysts were tested for methanol conversion and H2/CO selectivity via steam reforming of methanol (SRM) reactions in a fixed bed reactor. There is a distinct difference in the performance of these two supports. Bimetallic 3.33%Cu6.67%Ni/TiO2catalyst showed an impressive 99% H2selectivity at as low as 150°C and a maximum conversion of 92% at 250 °C but 3.33%Cu6.67%Ni/MCM-41 catalyst did not show any H2selectivity at 150°C and only ~12% conversion at 250°C. The effect of each support and relative metal loadings on the activity and selectivity of the SRM reaction products at different temperatures is discussed.

Hydrogen Production from Ethanol Steam Reforming over Ni-Cu/ZnO Catalyst

2011 ◽  
Vol 236-238 ◽  
pp. 1067-1072
Author(s):  
Li Ping Liu ◽  
Xiao Jian Ma ◽  
Peng Zhang ◽  
Ya Nan Liu
Keyword(s):  
Hydrogen Production ◽  
Steam Reforming ◽  
Fixed Bed ◽  
Surface Characteristics ◽  
Catalytic Performance ◽  
Fixed Bed Reactor ◽  
Molar Ratio ◽  
Ethanol Steam Reforming ◽  
Hydrogen Yield ◽  
Ethanol Steam

Hydrogen production by ethanol steam reforming over Ni-Cu/ZnO catalyst in the temperatures range of 250-550°C was studied on a fixed bed reactor. The effects of reaction temperature and water/ethanol molar ratio on hydrogen production were investigated. The structure and surface characteristics of the catalyst were measured by scanning electron microscopy (SEM), X-ray diffraction (XRD) and differential thermal analyzer (TG-DSC). The results show that the Ni-Cu/ZnO catalyst has good catalytic performance with higher hydrogen yield of 4.87molH2/molEtOH reacted. A comparison of hydrogen production from ethanol steam reforming over Ni-Cu/ZnO catalyst with over a commercial catalyst was made in this paper.

scholarly journals The Effects of Promoter Cs Loading on the Hydrogen Production from Ammonia Decomposition Using Ru/C Catalyst in a Fixed-Bed Reactor

Catalysts ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 321
Author(s):  
Yen-Ling Chen ◽  
Chin-Fang Juang ◽  
Yen-Cho Chen
Keyword(s):  
Hydrogen Production ◽  
Fixed Bed ◽  
Space Velocity ◽  
Ammonia Decomposition ◽  
Fixed Bed Reactor ◽  
Molar Ratio ◽  
Carbon Catalyst ◽  
Molar Ratios ◽  
Maximum Value ◽  
Ammonia Conversion

The hydrogen production from ammonia decomposition on commercial 5 wt.% Ru/C (C: activated carbon) catalyst with different cesium (Cs) loadings at lower temperatures of 325–400 °C in the fixed-bed reactor was experimentally investigated. Based on the parameters used in this work, the results showed that the ammonia conversion at 350 °C is increased with the increasing Cs/Ru molar ratio, and it reaches its maximum value at the Cs/Ru molar ratio of 4.5. After that, it is rapidly decreased with a further increase of Cs/Ru molar ratio, and it is even smaller than that of the pure Ru/C case at the Cs/Ru molar ratio of 6. The Cs promotion at the lower Cs/Ru molar ratios may be due to the so-called “hot ring promotion”. The possible mechanisms for Cs effects on the ammonia conversion at higher Cs/Ru molar ratio are discussed. At optimum Cs loading, the results showed that all the ammonia conversions at 400 °C are near 100% for the GHSV (gas hourly space velocity) from 48,257 to 241,287 mL/(h·gcat).

Hydrogen production by steam reforming of glycerol over Ni/Ce/Cu hydroxyapatite-supported catalysts

2013 ◽  
Vol 67 (7) ◽  
Author(s):  
Lukman Hakim ◽  
Zahira Yaakob ◽  
Manal Ismail ◽  
Wan Daud ◽  
Ratna Sari
Keyword(s):  
Hydrogen Production ◽  
Steam Reforming ◽  
Fixed Bed ◽  
Supported Catalyst ◽  
Fixed Bed Reactor ◽  
Bet Surface Area ◽  
Precipitation Method ◽  
Molar Ratio ◽  
Hydrogen Yield ◽  
Glycerol Conversion

AbstractHydroxyapatite-supported Ni-Ce-Cu catalysts were synthesised and tested to study their potential for use in the steam reforming of glycerol to produce hydrogen. The catalysts were prepared by the deposition-precipitation method with variable nickel, cerium, and copper loadings. The performance of the catalysts was evaluated in terms of hydrogen yield at 600°C in a tubular fixed-bed microreactor. All catalysts were characterised by the BET surface area, XRD, TPR, TEM, and FE-SEM techniques. The reaction time was 240 min in a fixed-bed reactor at 600°C and atmospheric pressure with a water-to-glycerol feed molar ratio of 8: 1. It was found that the Ni-Ce-Cu (3 mass %-7.5 mass %-7.5 mass %) hydroxyapatite-supported catalyst afforded the highest hydrogen yield (57.5 %), with a glycerol conversion rate of 97.3 %. The results indicate that Ni/Ce/Cu/hydroxyapatite has great potential as a catalyst for hydrogen production by steam reforming of glycerol.

scholarly journals Influence of molar ratio on dielectric, ferroelectric and magnetic properties of Co0.5Mg0.5Fe2O4/Ba0.85Sr0.15TiO3 composite ceramics

2019 ◽  
Vol 13 (3) ◽  
pp. 257-268
Author(s):  
Lang Bai ◽  
Rongli Gao ◽  
Qingmei Zhang ◽  
Zhiyi Xu ◽  
Zhenhua Wang ◽  
...  
Keyword(s):  
Sol Gel ◽  
Peak Position ◽  
Relaxation Peak ◽  
Molar Ratio ◽  
Composite Ceramics ◽  
Molar Ratios ◽  
Mean Grain Size ◽  
Higher Temperature ◽  
Two Phases ◽  
Two Peaks

In the present work, Co0.5Mg0.5Fe2O4/Ba0.85Sr0.15TiO3 (CMFO/BST) composite ceramics with different molar ratios (1:1, 1:2, 1:4, 1:6 and 1:8) were prepared by sol-gel method and sintered at 1150?C. The effects of molar ratio on the structure, dielectric and multiferroic properties were comparatively studied. The results indicate that all the synthesized composites mainly show bi-phase structure except slight presence of impurity phases. The surface of the specimens is relatively dense and the mean grain size is about 2 ?m. It decreases at first and then increases with the increased molar ratio. The dielectric constant shows decreased trend with increasing the molar ratio, while the dielectric loss presents the opposite behaviour. With the increase of molar ratio, the height of the relaxation peak decreases while the peak position shifts to higher temperature range. The relaxation peak evolves gradually from one to two peaks. The residual polarization increases with voltage but decreases with frequency. The maximal polarization of 1.28 ?C/cm2 is obtained in the specimen with the molar ratio of 1:8, due to the largest concentration of ferroelectric phase BST. The magnetization shows abnormal behaviour with the change in molar ratio. The largest saturation and remnant magnetization are 20.89 and 12.66 emu/g, respectively when the molar ratio is 1:2 due to the stronger interface interaction effect between the two phases.

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